Genetically modified food are food products derived from genetically modified organism and obtained from the latest technology for improving shelf life, nutritional content, color, flavor, and texture of food. The GMO refers to organisms in which productivity is increased by artificially separating and combining useful genes of animals and plants or microorganisms unlike developing by the existing crop breeding, that is, organisms having a new genetic trait obtained by inserting external derived gene into genetic material of reference organisms using modern biotechnology rather than traditional breeding or natural recombination. In addition, genetic recombination food refers to food produced by using the genetically modified organism as raw materials. In general, in order to increase productivity of genetically modified agricultural products, genes related with herbicide-resistance, insect resistance, disease resistance, cold resistance, and the like, have been introduced into the agricultural products. These days, many GMO foods are distributed, and among them, soybean foods are largely occupied. In addition to soybean, other various GMO foods including corn, papaya, pumpkin, and the like, are also distributed. Meanwhile, according to current controversies related to human health by the GMO, there is growing concern of consumers and farmers in respect to the GMO all over the world. Accordingly, in order to commercialize genetically modified crop, evaluation of environmental hazards, human health and food safety is required, and in relevant countries to import the genetically modified agricultural products, a regulatory system including GMO mandatory labeling has been established. In Korea, a label, of which food that has 3% or more of genetically modified plants introduced, needs to be marked as a genetically modified plant has been enforced. Other countries face a similar situation even though there is a difference in an incorporation tolerance. Accordingly, accurate analysis techniques for quantitatively measuring an incorporation ratio are required, in addition to qualitative analysis for measuring whether the GMO is incorporated.
The quantitative analysis of the GMO is largely divided into a protein analysis and a DNA analysis. In general, ELISA method targeting a protein which is expressed from a foreign gene introduced into the genetically modified plants has drawbacks that a detection intensity is lower than the PCR method, and a heat treatment may cause a denaturation of the protein. A technology of quantifying a foreign gene introduced into the genetically modified plant using a real-time PCR is widely employed. The real-time PCR renders a simultaneous amplication of the foreign gene and a quantitative monitoring the amount of amplification product. Quantitative analysis data may be obtained as a ratio of the foreign gene and endogenous genes with regard to predetermined amounts of a standard material by employing a real-time PCR, in which a fluorescent probe or certified reference material (CRM) or a standard plasmid is used as a standard material, in addition to a primer set required for the qualitative PCR.
Above all things, for accurate and precise analysis of the incorporation tolerance of the genetically modified plant, the standard material used for analysis is significantly important. Currently, GMO soy is neither cultivated and produced nor distributed in Korea. However, according to a government announcement, 932,000 tons of GMO soybeans (edible) corresponding to 77% of the total bean import volume, were imported in 2008. The GMO soy is used as a raw food material by extracting oils and protein. Soy protein is mainly used for bread, snack, processed meat products, baby food, and nutritional supplements, soybean fiber is used for wheat bread, cereals, snack processed goods, and soybean oil is used for salad oil, salad dressings, shortenings and raw materials of processed food, and the like. A GMO labeling requirement of soybeans and and a strict enforcement thereof are a sound public policy. Thus, there is a need for an improved standard material which can be used to accurately detecting and quantifying a foreign gene in a GMO. In addition, for a quantitative analysis of corns including various corn varieties, the use of one single standard material does not produce an accurate result because corns have different expression amounts depending on the variety. Also, a protein detection method has a limitation in detecting proteins expressed from a foreign gene in processed foods or raw materials containing GMOs, because recombinant proteins undergo denaturation or lysis during the food processing steps. That is, the standard material for analyzing genetically modified corns is required to have a long shelf-life as well as stability and homogeneity of the standard material itself, and such a standard material is needed.